JP2010280039A - Polishing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control with high accuracy a polishing load for pressing a rotating polishing tool to work. <P>SOLUTION: In the polishing device in which the polishing tool 1 is abutted on the workpiece to perform polishing working, a second member 4 for generating magnetic suction force in a radial direction is suitable for a first member 3 mounted to a tool shaft 2 of the polishing tool 1 and the second member 4 is rotated to rotate/drive the polishing tool 1. By moving the second member 4 in a thrust direction by a motor 12, the polishing load for pressing the polishing tool 1 to the workpiece is given. The polishing load is not influenced by the rotational number and rotation torque of the polishing tool 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polishing apparatus for polishing a workpiece with a rotating polishing tool.

  In general, in the polishing process, it is known as Preston's rule of thumb that the removal amount is proportional to the load pressing the tool against the surface to be processed, the number of rotations of the tool, and the processing time. In order to control the removal amount with high accuracy, the polishing load for pressing the tool against the surface to be processed and the rotation speed of the tool must be controlled with high accuracy.

  In the conventional polishing apparatus, a pressurizing mechanism for applying a load to the tool and a rotational drive mechanism for rotating the tool are provided at different positions on the tool shaft (see Patent Document 1). FIG. 3 shows a polishing head according to a conventional example. A tool 101 is fixed to one end of a shaft 102, and a rotating body 105 is fixed to the outer periphery of the shaft 102. The rotating body 105 is rotatably supported in a non-contact manner by the aerostatic bearings 108a and 108b. The shaft 102 is rotationally driven in a non-contact manner by a motor 106 composed of a rotor 106a fixed to the shaft 102 and a stator 106b. Further, by controlling the air pressure in the cylinder chamber 104, the rotating body 105 is moved to generate a load (polishing load) that presses the tool 101 against the surface to be processed. If such a structure is used, it is possible to control the load which presses a tool on a to-be-processed surface, and the rotation speed of a tool.

JP-A-63-232929

  However, in the conventional polishing head, the magnetic attraction force changes between the rotor 106a and the stator 106b due to the axial movement of the shaft 102. Further, when the rotational speed or rotational torque of the tool 101 is changed, the magnetic attractive force between the rotor 106a and the stator 106b changes. For this reason, there is a problem that it is difficult to control the load pressing the tool 101 against the surface to be processed with high accuracy.

  An object of the present invention is to provide a polishing apparatus capable of controlling a polishing load during polishing with high accuracy.

  The polishing apparatus according to the present invention is fitted to the polishing tool that rotates in contact with the workpiece, the first cylindrical member disposed on the tool shaft of the polishing tool, and the first cylindrical member. A second cylindrical member that performs, a means for generating a magnetic attractive force in a radial direction between the second cylindrical member and the first cylindrical member, and the second cylindrical member as the tool. A thrust driving means for driving in a thrust direction of the shaft portion; and a rotation driving means for rotating the polishing tool by rotationally driving the second cylindrical member, and the polishing tool is used by the thrust driving means. The polishing load for contacting the workpiece with the workpiece is controlled.

  According to the above configuration, even if the position of the polishing tool in the thrust direction changes, or even if the rotation speed or rotation torque of the polishing tool is changed, the polishing load that presses the polishing tool against the work surface can be kept constant. it can. Further, since the polishing load during the polishing process can be arbitrarily controlled, the processing accuracy can be greatly improved.

1 shows a polishing apparatus according to a first embodiment, where (a) is a schematic partial cross-sectional view showing a main part thereof, and (b) is a partially enlarged view showing means for generating a magnetic attractive force between a first member and a second member. It is a top view. It is a figure which shows the grinding | polishing apparatus by Example 2 and its modification in a cross section, respectively. It is a schematic cross section which shows the principal part of the grinding | polishing apparatus by one prior art example.

  As shown in FIG. 1A, the polishing head, which is a main part of the polishing apparatus, includes a tool 1 that is a polishing tool, a tool shaft 2 that constitutes a tool shaft portion, and a first cylindrical member. And the member 3. The tool 1 is fixed to one end of a tool shaft 2, and a first member 3 is arranged coaxially with the tool shaft 2 and fixed to the tool shaft 2. The second member 4, which is a second cylindrical member fitted to the first member 3, is fixed to the rotating body 5, and the second member 4 and the rotating body 5 move as a single body. The first member 3 and the second member 4 are arranged coaxially, and a magnetic attraction force in the radial direction acts between them. The rotating body 5 has a gear on its upper outer peripheral surface, and the rotational torque of the motor 6 serving as a rotational drive means is transmitted via the motor gear 7 to perform rotational motion.

  The second member 4 is rotationally driven by the motor 6 and rotates the tool shaft 2. The tool shaft 2 is supported in the radial direction by the static pressure air bearings 8a and 8b, and can be freely rotated and moved in the vertical direction. The rotating body 5 is rotatably supported by bearings 9a and 9b. The bearings 9a and 9b, the motor gear 7, the motor 6, and the nut 10 are integrally formed, and can be freely moved in the vertical direction by a linear guide (not shown). The nut 10 is moved in the vertical direction by the feed screw 11, and the second member 4 is moved in the vertical direction, which is the thrust direction, by the motor 12 as thrust driving means via the rotating body 5, the nut 10 and the feed screw 11. To do. The hydrostatic air bearings 8a and 8b, the linear guide, and the motor 12 are fixed to the housing 13, and the housing 13 can be positioned in the translational direction and the posture can be changed by means not shown.

  FIG. 1 (b) shows a means for generating a magnetic attractive force between the first member 3 and the second member 4, and twelve firsts are provided on the outer peripheral surface of the inner ring 30 that is integral with the first member 3. The magnets 31 are arranged, and twelve second magnets 41 are arranged on the inner peripheral surface of the outer ring 40 that is integral with the second member 4. The magnets 31 and 41 arranged in the circumferential direction are arranged such that a pair of magnets facing each other in the radial direction become opposite magnetic poles, and a magnetic attractive force in the radial direction works. If the inner ring 30 is at the center of the outer ring 40, the magnitude of the force in the thrust direction is zero. However, when the inner ring 30 translates in the thrust direction, a force in the thrust direction acts to pull the inner ring 30 back toward the center.

  The operation of the polishing apparatus of this embodiment will be described below. The position and orientation of the housing 13 are changed by means not shown, and the position and orientation of the housing 13 are determined so that the tool 1 comes close to the work surface of the work piece. At this time, a magnetic attractive force acts between the first member 3 and the second member 4, and the tool shaft portion constituted by the tool 1, the tool shaft 2, and the first member 3 works in the thrust direction. It remains in a position where the force and gravity acting on the tool shaft are balanced. Here, when the second member 4 is lowered by driving the motor 12, the tool shaft portion is lowered, the tool 1 comes into contact with the surface to be machined, and when the second member 4 is further lowered, the first member as described above. The tool 1 is pressed against the work surface by the thrust force acting on the member 3. By changing the relative position of the first member 3 and the second member 4 by the motor 12, the load (polishing load) on which the tool 1 is pressed against the surface to be processed can be controlled. Polishing is performed by rotating the tool 1 with the motor 6 while maintaining the relative positions of the first member 3 and the second member 4 in a state where the tool 1 is pressed against the processing surface with a desired polishing load.

  During the polishing process, even when the position of the tool 1 changes in the vertical direction or when the rotational speed or rotational torque of the tool 1 is changed, the polishing load that presses the tool 1 against the work surface can be kept constant. Arbitrary control is also possible. As described above, by controlling the polishing load that presses the tool 1 against the surface to be processed with high accuracy regardless of the tool position, the number of rotations of the tool, and the rotational torque, higher-precision polishing can be performed.

  In this embodiment, as shown in FIG. 2A, only the first displacement detection means 14 and the second displacement detection means 15 for detecting the relative displacement between the first member 3 and the second member 4 are added. Is different from the first embodiment.

  The first displacement detector 14 detects the displacement in the vertical direction of the upper surface of the rotating body 5 in a non-contact manner. The second displacement detection means 15 detects the vertical displacement of the upper end surface of the tool shaft 2 in a non-contact manner. Since the displacement of the second member 4 is equal to the displacement of the rotating body 5 and the displacement of the first member 3 is equal to the displacement of the tool shaft 2, the displacement detected by the first displacement detection means 14 and the second displacement detection means 15. By taking the difference, it is possible to detect a change in the relative position of the first member 3 and the second member 4. By driving the motor 12 so that the detected relative position between the first member 3 and the second member 4 is constant, the polishing load, which is the pressing load against the work surface of the tool 1, can be kept constant with higher accuracy. Is possible. If the relationship between the relative position of the first member 3 and the second member 4 and the polishing load is clarified, the polishing load can be arbitrarily controlled by the motor 12. As a result, the polishing amount can be changed as necessary.

  FIG. 2B shows a modification of the present embodiment. Instead of the displacement detection means 14 and 15, distance detection means attached to the attachment stay 16 for detecting the distance to the tool shaft 2. 17 is provided. Since the mounting stay 16 moves up and down as the nut 10 moves up and down, it moves up and down by the same distance as the up and down movement of the second member 4. By detecting a change in the relative position of the first member 3 and the second member 4 by the distance detection means 17, the polishing load that the tool 1 presses the work surface can be held constant or arbitrarily controlled. It becomes.

DESCRIPTION OF SYMBOLS 1 Tool 2 Tool axis | shaft 3 1st member 4 2nd member 5 Rotating body 6, 12 Motor 7 Motor gear wheel 13 Case 14, 15 Displacement detection means 17 Distance detection means

Claims (2)

A polishing tool rotating in contact with the workpiece;
A first tubular member disposed on the tool shaft of the polishing tool;
A second tubular member that fits into the first tubular member;
Means for generating a radial magnetic attractive force between the second cylindrical member and the first cylindrical member;
Thrust driving means for driving the second cylindrical member in a thrust direction of the tool shaft portion;
Rotation driving means for rotating the polishing tool by rotating the second cylindrical member,
A polishing apparatus for controlling a polishing load for bringing the polishing tool into contact with a workpiece by the thrust driving means. The first cylindrical member includes a first magnet disposed in a circumferential direction of the tool shaft portion,
The polishing apparatus according to claim 1, wherein the second cylindrical member includes a second magnet disposed so as to be a reverse magnetic pole facing the first magnet.

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